Automated manufacturing processes known as “pick-and-place” processes often include a mechanism that picks or selects an object and transfers it from one location to another in order for the object to be placed in a precise position.
Many manufacturing processes require the assembly of large numbers of miniature components, and the number of such components is likely to grow rapidly as the complexity of products increases. A key bottleneck to the assembly rate and cost is the ability to assemble multiple components in parallel. While many of the contemporary pick-and-place robots can assemble units at rapid rates of several parts per second, these rates will not scale to objects with millions of components. To alleviate this bottleneck, a massively parallel pick-and-place process is needed.
The term “miniature objects” refers to micro- and nano-scale objects. There are three main issues to consider when deciding on a transport method for miniature objects using traditional methods. First, the end effector must typically match either the entire or part of the object shape and has to be able to pick up the object without destroying or damaging it. Second, the devices currently designed to pick up these small objects tend to be extremely fragile, often as fragile as the objects they are trying to pick up. This leads to limitations on the speed of motion, since all objects must be carefully controlled. Finally, repeatability of the picking motion is essential for large scale operations. The repeatability and reliability of the end effector can be increased by using parallel pick-and-place operations.
There have been a number of devices invented in order to move hundreds of small objects. Some look at pick-and-place robotics to individually grasp and move each piece quickly, while others rely on self-assembly through energy minima. From suction to magnets to tweezers, numerous products attempt to quickly move large amounts of small objects efficiently and carefully. However, there is a limitation on size. Once objects get too small, for example, around the range of a millimeter and smaller, it becomes more difficult to handle these delicate objects and to quickly and accurately arrange the objects in a desired configuration. Furthermore, most inventions use single end effectors to pick up objects—greatly increasing the time to move objects—when two or more objects could be moved in parallel and in any configuration or pattern if properly controlled.
Common end effectors for small scale pick-and-place processes today include pipette vacuums, nano- or micro-fabricated tweezers attached to parallelogram arms, and electrostatic singular or dual cylinders. These techniques are difficult to parallelize in order to move many objects at once and lack a universal end effector which allows for picking up objects with different shapes.
Another technique involves the use of chemically activated micro-grippers. While this technique requires low energy input, it requires the submersion of materials into chemicals, which may degrade and deform components. Certain other techniques require external grippers or mechanisms to manipulate the components.
The quest to move small objects quickly, efficiently, and safely has been a goal of robotics and manufacturing since the beginning of mass production. The challenge has grown with the decreasing size of components of technological interest (i.e. electronic components). While there is a lot of diversity in the mechanism of transport such as the number of degrees of freedom in a robotic arm as well as the type and number of end effectors handling the object, there is still a lack of consistency, accuracy, and delicacy in moving micro- and nano-scale objects.
Thus, there is a need to quickly, efficiently and safely move miniature objects individually and in parallel as well as in any configuration or pattern. The present invention satisfies this demand.